initial gha workflow

.github/workflows/ci.yml

@@ -0,0 +1,16 @@
+name: CI
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Install Ruby!
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "3.2.2"
+
+      - name: rake check
+        run: rake check